1. Field of the Invention
This invention relates to a safety apparatus designed to be mounted on an elevator car, which car moves along guide rails; said safety apparatus comprising a frame, an area for wedge housings formed in the frame, and wedges placed in the wedge housings on each side of a guide rail; said wedges gripping the guide rail when the safety apparatus is activated, the wedges being placed relative to each other such that the wider end of one wedge points upwards while the wider end of the second wedge points downwards.
2. Description of Related Art
In certain countries, the regulations concerning elevators have been revised to help prevent accidents where,
(i) an elevator car crashes against the ceiling of the hoistway after an overspeed upward drive; and,
(ii) a passenger is injured by the doorway structures of an elevator car which has moved off from a floor with the doors open.
The new regulations also provide more freedom of design of the safety equipment, as they now accept even non-mechanical solutions.
The device of invention is designed to stop the motion of an elevator car unit, when necessary. To stop an elevator car unit, both the elevator car unit and the counterweight can be provided with safety gears as defined, for example, in FI publication print 74686. It is also possible to provide an overspeed governor with an electrically operated low speed trigger to guarantee safety in the doorway area. However, this is an expensive solution. Moreover, the low speed trigger occupies a large space in the hoistway since the counterweight, too, must be provided with similar safety gear.
An alternative possibility is to use known safety apparatuses together with rope arresters mounted in the machine room. However, this solution is expensive and difficult to implement in differen rope systems.